Avraham Harnoy

Contact Info

Email:

avraham.harnoy@njit.edu

Office:

319 Mech

Phone:

973-596-3350

Dept:

Mechanical Engineering

About Me

Dr. Harnoy is a professor in the Department of Mechanical and Industrial Engineering at New Jersey Institute of Technology where he has taught since 1986.He has been engaged in teaching, and research in tribology, artificial joint implants, bearing design and lubrication, fluid mechanics and rheology of viscoelastic fluid.

Dr. Harnoy has many years of diversified industrial and academic experience in several countries, has spent eight years of his career in industrial research and development positions in industry.The remainder of his career has been in academic positions, combining teaching and research.

The first significant scientific contribution of Dr. Harnoy is in flow of viscoelastic fluids. This work includes a basic contribution to continuum mechanics in the form of a new definition of time derivative for stress and strain-rate tensors for viscoelastic fluids.He applied this new definition to formulate new constitute models of viscoelastic fluids (J. Fluid Mechanics, 1976, vol. 76. p. 501).The new models agreed, for the first time, with experiments at high shear rate flow of viscoelastic fluids, such as in bearings and gears lubrication. Later, he applied this theory to analyze the performance of hydrodynamic lubrication with viscoelastic lubricants under steady and dynamic loads, and boundary layer flow.This work explained the improvement in the hydrodynamic lubrication performance of multigrade oils. He also applied this theory for analyzing viscoelastic boundary layers. This viscoelastic fluid equation became the basis of many published research work by other scientists around the world.

The second significant contribution has been the developing a dynamic friction model (Wear, J. of science and Technology, Oxford, Vol. 12, 1994).This model has been used later in a project, "Modeling and compensation of Friction in Control", in cooperation with Dr. Friedland. This project has been supported by a grant from the National Science Foundation. Dr. Harnoy is currently continues this research by applying this model to artificial joints, which operate under dynamic loads.

On the experimental side, Dr. Harnoy has extensive experimental experience. He developed laboratories, and designed a variety of testing rigs.He has published his theoretical and experimental research.

Dr. Harnoy served as a consultant to several companies including consulting to NASA Ames on the gyroscope bearings in the space station, as well as consultancy to Foster Wheeler Energy Corporation in bearing design of large bearings for coal pulverization in power stations.

Dr. Harnoy published a textbook “Bearing design in Machinery, Engineering Tribology and Lubrication” Published by Marcel Dekker Inc. 2003, and later took over by the publisher Taylor & Francis NRC.

Dr. Harnoy holds a B.S. (1961), M.S. (1967) in Mechanical Engineering and Doctor of Science (1972) in Mechanics, all from the Technion-Israel Institute of Technology.His doctoral advisor was the late Professor Marcus Reiner, who is the well-known founder of the discipline of rheology.

Education

Technion, Israel Institute of Technology, DSc 1972

Technion, Israel Institute of Technology, MS 1977

Technion, Israel Institute of Technology, BS.1961

Research Interests

Dr. Harnoy is investigating all aspects of bearings and bearing lubrication in machinery. In particular, design, heat transfer, material selection, testing and analysis of hydrodynamic, hydrostatic and rolling-element bearings as well as unique designs such as hybrid bearings. Design and development testing machines for dynamic friction, tribology of bearing materials and lubricants. He is conducting research in modeling and measurement of dynamic friction in bearings. Dynamic friction models are used for friction compensation for enhancing the precision of motion in control systems. This work includes simulation and measurements of dynamic friction effects such as stick-slip friction and friction induced vibrations. In addition, research is conducted in flow behavior of viscoelastic fluids such as multigrade oils, as well as synthetic lubricants.

Current Research

Recent activity is the investigation of the performance, design and material properties of orthopedic joint implants.